Influence of glycerol on plasma electrolytic oxidation coatings evolution and on corrosion behaviour of coated AM50 magnesium alloy

摘要

PEO coatings were obtained from base silicate electrolyte (bPEO) and glycerol added silicate electrolytes (gPEO) for different processing times. PEO coatings' evolution and their corrosion behavior were systematically studied as a function of PEO processing time. Smaller maximum pore size and higher pore density have been discerned for gPEO compared to bPEO for all the PEO processing time. Glycerol addition resulted in reduced coating thickness, promoted periclase, MgO, formation and suppressed forsterite, Mg2SiO4, amorphization. From electrochemical impedance spectroscopy study, it was found that gPEO had better corrosion resistance as compared to bPEO.